Diabetes is a general term for disorders in man having excessive urine excretion as in diabetes mellitus and diabetes insipidus. Diabetes mellitus is a metabolic disorder in which the ability to utilize glucose is more or less completely lost. About 2% of all people suffer from diabetes.
Since the introduction of insulin in the 1920's, continuous strides have been made to improve the treatment of diabetes mellitus. To help avoid extreme glycaemia levels, diabetic patients often practice multiple injection therapy, whereby insulin is administered with each meal.
In the treatment of diabetes mellitus, many varieties of insulin preparations have been suggested and used, such as regular insulin, Semilente.RTM. insulin, isophane insulin, insulin zinc suspensions, protamine zinc insulin and Ultralente.RTM. insulin. Some of the commercial available insulin preparations are characterized by a fast onset of action. Ideally, exogenous insulin is administered at times and in doses that would yield a plasma profile which mimics the plasma profile of endogenous insulin in a normal individual. Insulin preparations containing analogs of human insulin have shown an absorption profile very close to the normal plasma profile, e.g. Lys.sup.B28 -Pro.sup.B29 human insulin and Asp.sup.B28 human insulin. However, these new insulin preparations still have to be injected in connection with a meal. In order to circumvent injections, administration of insulin via the pulmonary route could be an alternative elucidating absorption profiles which mimic the endogenous insulin without the need to inject the insulin.